MONTPELIER — A state trooper was justified in using force against a man who died of a heart attack last year after being hit with a stun gun, the Vermont attorney general’s office said Friday.

The review found Trooper David Shaffer was within his rights to use his stun gun on Macadam Mason in June because the distraught man failed to comply with orders and made threatening movements toward the trooper.

Reviews by the attorney general and the Orange County state’s attorney’s office both concluded criminal charges were not warranted against Shaffer because under state law a person is entitled to defend himself if he believes he is in immediate danger of bodily harm.

Mason is believed to be the first person to die after being struck by a stun gun in Vermont. The Thetford man’s death has raised questions about police use of stun guns, meant to be a nonlethal alternative to deadly force.

The head of the Vermont chapter of the American Civil Liberties Union said he didn’t think the trooper acted correctly and the police were not being held accountable.

Attorney General William Sorrell is planning to hold a public forum in March at the Statehouse in Montpelier with Allen Gilbert, the executive director of the Vermont chapter of the American Civil Liberties Union; Ed Paquin, executive director of Disability Rights Vermont; state Sen. Alice Nitka; and Rep. Bill Lippert to discuss the use of stun guns as a law enforcement tool.

“One of the things I think the report shows is the lack of police accountability,” Gilbert said Friday. “Just because a decision was made no criminal charges would be filed it doesn’t mean that police acted correctly.”

The head of the Vermont State Police said the agency was working with the mental health community to improve training and will continue to evaluate cases to make meaningful decisions regarding the use of stun guns.

“The actions of our troopers helped protect citizens in a highly dangerous and life-threatening event,” said Col. Tom L’Esperance. “The difficult decision to use force is something that stays with our members, throughout their careers. And we will continue to provide support and training to our members, as needed.”

Shaffer is on paid administrative leave. Police would not say why.

Police were called to Thetford after being told by personnel staffing a crisis line that an unidentified male, who sounded intoxicated, had said he was suicidal and homicidal, had access to weapons and hoped police would shoot him.

After troopers arrived, the owner of the house, Theresa Davidonis, Mason’s longtime companion, told police dispatchers there were no weapons in the house and she did not want troopers to enter.

Davidonis asked the troopers to leave because she felt their presence was aggravating Mason. Because of what they were told, the troopers returned to the home to confirm Mason was safe.

Shaffer helped set up a perimeter in the woods near the house and later saw Mason and ordered him to lie on the ground.

“Instead, he stood, used profanities and asked (Trooper) Shaffer to shoot him,” said the attorney general’s review.

Mason took at least two steps toward Shaffer, according to accounts of the incident.

Shaffer was carrying a rifle, but he put it down and instead fired the stun gun, hitting Mason in the chest.

Shaffer and another trooper found him to be unresponsive and immediately began CPR. Mason was taken to Dartmouth-Hitchcock Medical Center and pronounced dead.